-38.53% is the change from 815 to 501
Calculation steps:
[( 501 - 815 ) ÷ 815] x 100 = -38.53%
Formula
Percentage change = [(501 - 815) / 815] x 100
Subtract the new number by the original number
501 - 815 = -314
-314 ÷ 815 = -0.3852760736196319
-0.3852760736196319 x 100 = -38.53%